At present, Internet Protocol Version 6 (IPv6) has been already supported in various computers such as a Personal Computer (PC) and a portable equipment, and IPv6 packets already flow in communication networks. As to global addresses that are newly acquired from now on, only IPv6 addresses may available. Therefore, IPv6 is expected to be adopted more rapidly from now on, in communication networks. According to this, an environment where IPv4 and IPv6 are used together is expected to expand further. Hereinafter, a computer such as a portable equipment or a virtual machine will be denoted also as a node. In addition, a node which supports IPv6 will be denoted as IPv6 node.
With the adoption of the IPv6 in more networks, there is an increasing demand for a method of managing a network that includes an IPv6 node. For example, Patent Literature 1 discloses a technology of detecting unauthorized connection and shutting down a terminal connected in an unauthorized manner in an IPv6 network.
Other technologies for handling IPv6 are disclosed in Patent Literatures 2 to 8 below.